The present invention relates to a mounting frame for a printhead, specifically a thermal printhead, used with a thermal transfer ribbon or such as a dye sublimation ribbon, which has exposed, sensitive heat elements or resistive elements along a print line that engage a ribbon for printing on a substrate supported on a platen. The printhead is on a frame so it can be pivoted away from its working position to provide access to ribbon take-up and supply rolls and is guided so that the print line of heat elements remains oriented to shield the elements when the printhead is raised.
Prior art thermal printers have printheads mounted on frames and pivoted between a working position and an open position where the ribbon and other interior printer components are accessible. However, the housings or supports for the printheads presently are fixed to a pivoting frame so that when the printhead is in its working position it is substantially vertical, and facing the interior of the printer, and when the frame is pivoted 90xc2x0 to its open position, the pivot head is substantially horizontal. The sensitive heater resistive elements overlie the region in which an operator must work to replace a ribbon and are exposed so they can be contacted by the operator. This exposure creates the potential for the printer resistive elements to be bumped and damaged by jewelry, tools or other hard objects the user might employ.
The printheads are expensive, and if the thermal elements are damaged the printhead has to be replaced. Access to the ribbon take-up and supply rollers is necessary, and the present invention provides a mounting guide for the printhead so that the printhead remains vertically oriented and the resistive elements are out of the way or shielded from impacts and contact with the operator when the printhead is raised to its open position.
The present invention relates to a printhead mounting, particularly for thermal printheads that have heater resistive elements along the print line, which guides the printhead as it is moved to an open position for permitting access to the ribbon supply and other components of the printer. The printhead is pivotally mounted to a pivot frame and as the pivot frame is moved, the printhead is guided with a guide shaft moving in a cam track so that the printhead remains oriented with the print line heater resistive elements facing toward the interior of the printer. The resistive elements face in a direction so they are shielded by the printhead body throughout the path of travel between the printhead working position and an open position. The printhead is also positively guided with the guide shaft as the head is returned to working position. The guide shaft prevents the head from moving independently and hitting the rear wall of the printer. The printhead is spring-loaded to keep it oriented properly.
The printhead has a mounting frame, with side plates on the sides of the printhead for adjustably mounting the printhead relative to the pivot frame. The frame side plates can be precisely adjusted during assembly and the printhead fixed in place so that the print line on the printhead is properly located on a support platen when in a working position to allow for optimized print location and for the head to be movable at the same time.
The printhead operates in a conventional manner for thermal printers, and is adapted to be used with standard mountings for the platen, and with existing ribbon supply and take-up rollers. The pivot mounting of the printhead relative on the pivoting frame is possible because the printhead is guided in guide tracks as tracks as it approaches its working position. Then as the printhead is closed, the printhead moves into a guide that causes the same precise location as it had each time it was closed. Having the printhead positioned out of the way of the work area when the printhead is in its open position not only protects the resistive elements, but also makes the interior of the printer more accessible.